library(foreign)
library(readstata13)

d <- read.dta13("Barber_Bolton_Thrower_Replication_Data_LSQ.dta")

plot(density(d$house_polarization[d$divided_gov1 == 0], na.rm = T), lwd = 3, lty = 2, 
	main = "Polarization Distribution Under Unified\nand Divided Government",
	xlab = "Absolute Distance Between Party Medians")
lines(density(d$house_polarization[d$divided_gov1 == 1], na.rm = T), lwd = 3)
legend("topright", c("Divided Government", "Unified Government"),
	lty = c(1, 2), lwd = c(2, 2))
